Known as Kitzmiller Road, the state highway runs 5.67 miles (9.12 km) from the West Virginia state line at the North Branch Potomac River in Kitzmiller, where the highway continues south as West Virginia Route 42 (WV 42), north to MD 135 on top of Backbone Mountain.

After passing Main Street, MD 38 begins its steep, curvy ascent of Backbone Mountain as a two-lane undivided road.

The southbound direction of the state highway features a mandatory truck stop to check brakes at the top of the 2-mile (3.2 km) hill.

The state highway descended Backbone Mountain toward Altamont and continued west to Deer Park following what is now MD 135 and Edgewood Drive into the center of the town.

[4][5] The highway was extended east to the top of Backbone Mountain by 1930; this construction included the bridge over the Baltimore and Ohio Railroad at Altamont.